Global warming chills the north

WHAT WOULD we do without some comic relief during this big freeze? Fortunately, we have Telegraph columnist Christopher Booker. In his column on 2 January, he attacked the Met Office: "The year 2007, it predicted, would be 'the warmest ever' - just before global tempratures plunged by more than the entire net warming of the 20th century."

Pete Mason

Ignore the misspelling - we can all struggle with the word 'temperature', even the elite educated at Corpus Christi College, Cambridge, like Booker. But Booker could mislead his faithful readers - purely unintentionally, of course! - into thinking that 2007 turned out to be cold. 2007 was the second warmest year on record. It tied with 1998, while 2005 was the hottest on record. The year 2007 showed that the recent trend of record-breaking years has not abated. The Met Office's prediction (and it only said it was 'likely') was not so far off.

But, Booker protests - surely it should not snow if there is global warming? Yes, it can snow - it can snow a great deal. But he is not interested in the science.

What is happening to our weather? Why is there record flooding, snow falls, and hurricanes, let alone record heatwaves and droughts, leading to record crop failures and food prices?

When you heat up a planet the weather becomes stormier. Weather systems are more energetic. Relatively stable weather systems are displaced by more unstable ones - the rain no longer falls where it has fallen for centuries. Drought and crop failures follow. This might not greatly concern the wealthier readers of the Telegraph and journalists like Booker but it hits those with less disposable income much harder.

More water evaporates and falls as rain or snow, in great storms. Instead of reinvigorating the ground, flood water washes away the top soil, denuding fertile ground, while bringing death and destruction, particularly to low lying areas like Bangladesh.

The recent cold weather is due to an unusual shift in weather systems which prevented the prevailing winds, usually flowing over the warm waters of the Gulf Stream, from warming our islands. Instead, the winds are greeting us via the Arctic Circle.

2007 marked the greatest loss of ice in the Arctic Circle on record - so far. A vicious circle has cut in. The loss of ice further warms the arctic waters. Not enough, of course, to unchill the British Isles. But it is accelerating the trend of arctic ice loss.

This has also accelerated the release of methane - a greenhouse gas 25 times more powerful than carbon dioxide - once trapped in the permafrost.

Now scientists say the icy melt water released from Greenland's ice sheets could shut off the Gulf Stream. Perhaps this decade or next, or maybe much later, the result could send the north Atlantic region into an ice age while the rest of the world slowly cooks.